Anisotropic thermal conductivity of AlGaN/GaN superlattices.

High thermal conductivity is an important parameter for nitride-based power electronic and deep-UV light emitters. Especially in the latter case short period superlattices and multicomponent alloys are used and the knowledge of the thermal properties of the binary compounds is sufficient. In-plane and cross-plane thermal conductivity of AlGaN/GaN superlattices were measured by differential two-wire 3ω method in the temperature range from 147 to 325 K. Samples were grown by metalorganic vapor phase epitaxy; the structure quality and accuracy of superlattice structures preparation were verified by means of HRXRD and transmission electron microscopy. It was observed, that value of thermal conductivities decrease with decreasing period thickness, while temperature dependencies differ from each other-in-plane thermal conductivity decreases, and cross-plane-increases with increasing temperature. Callaway method was used for thermal conductivity calculation; dependence of boundary scattering rate on the phonon wavelength was taken into account. Minimum thermal conductivity was added to calculated values to include the influence of high frequency acoustic phonons and optical phonons on the heat transport. Calculations are in good agreement with experimental results.

How to diagnose splenic abscesses?

Splenic abscess is a rare but potentially fatal entity, occurring mainly in patients with underlying risk factors. Mortality of the disease depends on the time of diagnosis and treatment. Due to low sensitivity and specificity of clinical symptoms and laboratory markers, imaging plays the vital role in the diagnostic work-up. The aim of this article is to give a concise overview of the methods of splenic abscess diagnosis.

Cellulitis and bacteria in peripheral lymphedema.

Counterpoint to the article: Peculiar Clinical Features of Cellulitis in Peripheral Lymphedema, K. Suehiro, et al. Lymphology Vol 51, No 2, pp 47-53.

Local microscopic properties and annealing effect of Rb0.85Fe1.9Se2 single crystals.

Investigation of mesoscopically phase-separated Rb0.85Fe1.9Se2 single crystals has been performed and two iron sites: nonmagnetic and magnetic ones, were observed by Mössbauer spectroscopy. The softening of the nonmagnetic one, having clearly more soft dynamics, was found to be gained further by the annealing of the single crystals at phase separation temperature, T p, leading to the reduction of size of initially separated domains and their more homogenous distribution in the tetragonal matrix of the studied sample. The magnetic Fe sites of Rb0.85Fe1.9Se2 show strong magnetic texture, indicating the perpendicular to the ab-plane orientation of the iron magnetic moments. It was found that the annealing at T p causes a systematic decrease of the isomer shift of the doublet by 0.02(1) mm s-1.

Determination of hyperfine fields orientation in nuclear probe techniques.

One of the most popular nuclear probes, 57Fe is used for the investigation of orientations of hyperfine fields and also for the determination of other important properties. In particular, the orientation of iron magnetic moments can be unambiguously determined, including its signs. Experiments with polarized radiation are presented with regard to selected systems. Orientation of electric field gradient is used for acquiring information about the shape of the texture-free spectra. Applications on the analysis of iron-based superconductors are presented.

Temperature dependent local atomic displacements in ammonia intercalated iron selenide superconductor.

Recently, ammonia-thermal reaction has been used for molecular intercalation in layered FeSe, resulting a new Lix(NH3)yFe2Se2 superconductor with Tc ~ 45 K. Here, we have used temperature dependent extended x-ray absorption fine structure (EXAFS) to investigate local atomic displacements in single crystals of this new superconductor. Using polarized EXAFS at Fe K-edge we have obtained direct information on the local Fe-Se and Fe-Fe bondlengths and corresponding mean square relative displacements (MSRD). We find that the Se-height in the intercalated system is lower than the one in the binary FeSe, suggesting compressed FeSe4 tetrahedron in the title system. Incidentally, there is hardly any effect of the intercalation on the bondlengths characteristics, revealed by the Einstein temperatures, that are similar to those found in the binary FeSe. Therefore, the molecular intercalation induces an effective compression and decouples the FeSe slabs. Furthermore, the results reveal an anomalous change in the atomic correlations across Tc, appearing as a clear decrease in the MSRD, indicating hardening of the local lattice mode. Similar response of the local lattice has been found in other families of superconductors, e.g., A15-type and cuprates superconductors. This observation suggests that local atomic correlations should have some direct correlation with the superconductivity.

Hyperkeratosis in human lower limb lymphedema: the effect of stagnant tissue fluid/lymph.

BACKGROUND: Hyperkeratosis of skin in lower limb lymphedema is one of the sequelae of tissue fluid/lymph (TF/L) stasis, but its mechanisms remain unknown. It is noteworthy, nonetheless, that human TF/L contains high levels of growth factors and cytokines, and may serve as the physiological environment for keratinocyte (KC) proliferation. OBJECTIVE: The aim of the study was to investigate the effect of human TF/L on human KC proliferation, differentiation and on the expression of epidermal stem cell markers on them. METHODS: KC were isolated from lymphedema and normal skin, and cultured for 1-14 days in TF/L with neutralized Interleukin 1ß, Interleukin 6, tumour necrosis factor α (TNF-α), keratinocyte growth factor (KGF) or tumour growth factor ß (TGF-ß). Alternatively, KC receptors for these factors were blocked. RESULTS: The number of KC cultured in TF/L was increased, as was the percentage of mitotic figures. There was a higher percentage of p63, CD29, Ki67, PCNA, CK6, CK17, CK16 and a lower of CK10, CK14, filaggrin and involucrin-positive KC. Neutralization of TF/L IL-1ß, IL-6, TNF-α and KGF as well as blockage of their receptors resulted in decreased percentage of mitotic KC. TGF-ß had a limited effect on KC proliferation. CONCLUSION: Hyperkeratosis in lymphedema may be the effect of a high concentration of cytokines in the stagnant TF/L tissue, but not because of presumed changes in the KC.

[Molecular diagnostics of lung cancer]. / A tüdorák molekuláris diagnosztikája.

Development of the target therapies of lung cancer was a rapid process which fundamentally changed the pathological diagnosis as well. Furthermore, molecular pathology became essential part of the routine diagnostics of lung cancer. These changes generated several practical problems and in underdeveloped countries or in those with reimbursement problems have been combined with further challenges. The central and eastern region of Europe are characterized by similar problems in this respect which promoted the foundation of NSCLC Working Group to provide up to date protocols or guidelines. This present paper is a summary of the molecular pathology and target therapy guidelines written with the notion that it has to be upgraded continuously according to the development of the field.

Transplantation of keratinocyte spore-like stem cells.

BACKGROUND: Wound granulation tissue should be covered by epidermal cells migrating from the basal layer of the epidermis or hair "bulge" of the wound edge. However, new epidermal islands are frequently formed on the granulation tissue remote from the wound edge. Thus, current theory of "bulge"-originating stem cells does not necessarily correspond to the histological pictures of the healing wound. We took imprints of a leg ulcer surface and found single dispersed, large nucleated cells, some of them in mitosis. These cells resembled those from epidermal spinosum layer. The question arouse as to whether these cells might be the "spore-like" stem cells creating epidermal island. We found similarly shaped cells among the keratinocyte preserved in pulverized sodium chloride as the only surviving population in culture and revealing enzymatic activity. The aim of this work was to study whether the population of human keratinocytes surviving sodium chloride preservation and transplanted to SCID mice may form epidermis. METHODS: The 12-month sodium chloride-preserved and cultured keratinocytes (KC) were transplanted to the wound on the dorsum of SCID mice for 14 and 21 days. RESULTS: Ninety-five percent of cultured KC were enzymatically active "large" cells; they did not express p63 and CD29 claimed as specific for stem cells, and they did not proliferate. Transplanted to the center of the wound, they formed small KC islands and became confluent after 14 days. CONCLUSIONS: The "large" epidermal keratinocytes survived the 12-month preservation in anhydrous sodium chloride. Transplanted to the wound, they formed epidermal islands of human phenotype. These cells may be the so-called "spore-like" stem cells.

Intrasplenic transplanted adult rat isolated hepatocyte fraction but not cholangiocytes forms bile canaliculi.

BACKGROUND: Hepatocyte transplantation (HT) has been performed in patients with liver-based metabolic disease and acute liver failure as a potential alternative to liver transplantation in countries in which ethical regulations do not allow organ transplantation. One of the problems remains that substances normally secreted by the surviving hepatocytes to bile cannot be removed because of lack of bile canaliculi. We found that ligation of the recipient's common bile duct in hepatocyte transplantation recipients is followed by formation of bile canaliculi. The question arose as to whether the signal released from the obstructed bile vasculature activated the transplanted hepatocytes (HC) or cholangiocyte (CH) to form bile canaliculi. METHODS: We transplanted separately isolated autologous HC and CH to spleens and observed the structural organization of the grafted cells. RESULTS: HC formed glycogen-rich clusters but not cords usually not attached to the CH of the new bile canaliculi. Separate clusters of bile canaliculi with keratin 7 and 19-positive and gamma-glutamyl transpeptidase-positive cells were observed. Transplanted CH remained keratin 7 and 19-positive and gamma-glutamyl transpeptidase positive but did not form canaliculi. CONCLUSIONS: The transplanted HC fraction may contain hepatic progenitor cells for cholangiocytes, but they become activated only under the condition of bile stasis by an as-yet undefined factor.

Training and practice of cytotechnologists: a discussion forum focused on Europe.

OBJECTIVES: To discuss the role and training of cytotechnologists (CTs) in Europe, to identify areas of good practice and to provide an informed opinion to those providing guidelines for training and practice in Europe. METHODS: All members of the Editorial Advisory Board of Cytopathology were invited to take part in a 'discussion forum' for which six topics were circulated in advance concerning the roles of CTs with regard to: (1) pre-screening slides; (2) 'signing out' reports; (3) carrying out ancillary techniques; (4) supervising laboratory staff; (5) taking part in rapid on-site evaluation (ROSE) of fine needle aspirates (FNAs); and (6) whether CTs were trained specifically in cytopathology or in general histopathology. Notes of the meeting were circulated by email and a final report was agreed by 22 participants from 17 predominantly European countries. RESULTS: Training for CTs throughout Europe was variable, especially for non-gynaecological cytology, which was inconsistent with the range of activities required. The participants recommended graduate entry, preliminary training in general laboratory technology, and subsequent training to take account of the probability and, in some centres, the reality of primary cervical cancer screening changing from cytology to human papillomavirus (HPV) testing. They further recommended that CTs should perform HPV tests and take part in ROSE for FNAs, and they supported the European Federation of Cytology Societies developing guidelines for training and practice. CONCLUSION: With CT training added to a university-based education in laboratory or biomedical science, a career in cytotechnology should be an attractive option involving a diverse range of laboratory and clinically based activities.

Lymphovenous microsurgical shunts in treatment of lymphedema of lower limbs: a 45-year experience of one surgeon/one center.

RATIONALE: The use of microsurgical lymphovenous shunts is one of the generally accepted treatments for limb lymphedema. AIM: The 45-year personal experience of one surgeon in indications, technique and results of lymphovenous shunt operations in lower limb lymphedema of varying etiology is presented. MATERIAL: One thousand three hundred patients were followed up in the period 1966-2011. Patients were classified into groups according to the etiology of lymphedema as postinflammatory/posttraumatic, postsurgical, idiopathic and hyperplastic. Decrease in limb circumference, heaviness and pain, and increase in joint flexing were evaluated. RESULTS: The most satisfactory results, reaching 80-100% improvement, were obtained in the congenital non-hereditary hyperplastic lymphedema group, with large lymphatics not previously damaged by infection. Results were also satisfactory in the group of cancer patients after iliac lymphadenectomy, reaching 80%. A less satisfactory outcome was observed in the postinflammatory group, not exceeding 30-40%. In idiopathic lymphedema results were satisfactory in only a few cases. CONCLUSIONS: Patients with lymphedema with local segmental obstruction but still partly patent distal lymphatics and without an active inflammatory process in the skin, subcutaneous tissue and lymph vessels present satisfactory results.

Magnetic resonance lymphography (MRL): point and counter-point.

Two preeminent lymphologists debate the findings, implications, interpretations, and value of magnetic resonance lymphography (MRL) in the evaluation of peripheral lymphedema. Their contrasting views are discussed in the context of different lymphatic imaging modalities including MRL, lymphoscintigraphy, and microscopic anatomy.

Chronic lower limb wounds evoke systemic response of the lymphatic (immune) system.

Wound healing should not be considered as a process limited only to the damaged tissues. It is always accompanied by an intensive local immune response and in advanced stages, the systemic lymphatic (immune) structure. In this review we present evidence from our own studies as well as pertinent literature on the role of skin and subcutaneous tissue lymphatics at the wound site and of transport of antigens along with collecting afferent lymphatics to the lymph nodes. We also speculate the role of lymph nodes in raising cohorts of bacterial and own tissue antigen-specific lymphocytes and their participation in healing and not infrequently evoking uncontrolled chronic immune reaction causing a delay of healing. It is also speculated as to why there is a rapid response of lymph node cells to microbial antigens and tolerance to damaged-tissue-derived antigens occurs.

Skin own bacteria may aggravate inflammatory and occlusive changes in atherosclerotic arteries of lower limbs.

AIM: Seroepidemiological studies have given rise to the hypothesis that microorganisms like Chlamydia pneumoniae (CP), Helicobacter pylori (HP), cytomegalovirus (CMV), HCV types 1 and 2, and bacteria involved in dental or other unspecified infection sites may initiate or maintain the atherosclerotic process in lower limb arteries. However, not much attention has been attached to the patient's own limb skin and deep tissues bacterial flora, activated in ischemic tissues. This flora may enhance the inflammatory and thrombotic process in the atherosclerotic arteries. Lower limb tissues are exposed to microorganisms from the environment (foot) and microbes on floating epidermal cells from the perineal and anal regions. The aim of this paper was to identify microbial cells and their DNA in perivascular tissues and arterial walls of lower limbs. METHODS: Bacterial cultures and PCR method for detection of 16sRNA and immunohistopathological staining for identification of immune cells infiltrating vascular bundles. RESULTS: 1) specimens of atherosclerotic calf and femoral arteries contained bacterial isolates and/or their DNA, whereas, in control normal cadaveric organ donors' limb arteries or patients' carotid arteries and aorta bacteria they were detected only sporadically; 2) lower limb lymphatics contained bacterial cells in 76% of specimens, whereas controls only in 10%; 3) isolates from limb arteries and lymphatics belonged in majority to the coagulase-negative staphylococci and S.aureus, however, other highly pathogenic strains were also detected; 4) immunohistopathological evaluation arterial walls showed dense focal infiltrates of granulocytes and macrophages. CONCLUSION: Own bacterial isolates can be responsible for dense neutrophil and macrophage inflitrates of atherosclerotic walls and periarterial tissue in lower limbs and aggravate the ischemic changes.

The pathophysiology of lymphedema - 2012.

Lymphedema of the limbs has become a frequent pathological condition after soft tissue inflammation, trauma, removal of lymph nodes in cancer and long-lasting ulcerations. Lymphatics draining the diseased tissues become occluded. Microsurgery helps in the formation of anastomoses and collaterals bypassing the obstruction site. Surgeons operating on the lymphatics should be aware of the tissue fluid/lymph formation mechanism, hydraulics of tissue fluid/lymph, tissue metabolism and waste material utilization, immune function in terms of elimination of microbial and tumor antigens and raising tolerance to own tissue antigens of injured tissues necessary for wound healing as well as classification of diseases of lymphatics. In this review we present the actual definition of the lymphatic system, how it is changed in lymphedema, and, in particular, tissue fluid/lymph biochemistry, pressure and flow, histopathology and tissue fluid location, and finally how to manage the most common complication dermato-lymphangioadenitis. Detailed knowledge of the anatomy of upper limb limphaties should prevent their damage and loss of function.

Pathways of lymph and tissue fluid flow during intermittent pneumatic massage of lower limbs with obstructive lymphedema.

Questions remain on the use of sequential pneumatic compression including where does the fluid flow to and whether fluid can be moved to the non-swollen tissues of the hypogastrium and gluteal region? During pneumatic massage of the limb, we studied pathways of lymph and mobile tissue fluid flow using lymphoscintigraphy: a) from the calf and thigh across the inguinal region to the healthy non-swollen tissues of the hypogastrium and b) in the hypogastrium to the lateral and upper abdominal quadrants. To examine if there was effective fluid flow during pneumatic massage, plethysmographic flow measurements were also carried out. We demonstrated that: (i) pneumatic compression moved isotope in lymph remaining in functioning lymphatics and in tissue fluid in the interstitial space toward the inguinal region and femoral channel, (ii) there was no isotope crossing the inguinal crease or moving to the gluteal area, and (iii) isotope injected intradermally in the hypogastrium did not spread during manual massage to the upper and contralateral abdominal quadrants. In conclusion, intermittent pneumatic compression is effective in pushing mobile tissue fluid and relocating large fluid volumes toward the groin. However, the question that still remains is how to facilitate further flow toward the non-swollen tissues and thereby increase local absorption of fluid.

The lymphovenous microsurgical shunts for treatment of lymphedema of lower limbs: indications in 2011.

The microsurgical lympho-venous shunts have become one of the generally accepted modalities in treatment of limb lymphedema. This review highlight the indications for this procedure after over 40 years. This study was based on the personal experience of one surgeon and on the review of the literature. Patients with postinflammatory, postsurgical, idiopathic and hyperplastic lymphedema of lower limbs were included in the study. Basing on the review of results of the last 40 years the contemporary indications are: 1) lymphedema with local segmental obstruction but still partly patent distal lymphatics seen on functional lymphoscintigraphy (standard walking or pneumatic compression) and without an active inflammatory process in the skin, subcutaneous tissue and lymph vessels (DLA-dermatolymphangioadenitis); 2) classified according the etiology of lymphedema, this operation can bring about satisfactory results in cases of hyperplastic, postsurgical and postinflammatory types of lymphedema, whereas primary idiopathic lymphedema of non-genetic type should be treated with conservative means, although in a small number of cases an improvement was observed after lympho-venous shunting as long as 10 years. Microsurgical lymph node or lymphatic vessel to vein shunts have their established position among the therapy modalities for lymphedema of lower limbs in a strictly defined group of patients using lymphoscintigraphic imaging.

Survey of medical training in cytopathology carried out by the journal Cytopathology.

This report of the Editorial Advisory Board of Cytopathology gives the results of a survey of medical practitioners in cytopathology, which aimed to find out their views on the current situation in undergraduate and postgraduate training in their institutions and countries. The results show that training in cytopathology and histopathology are largely carried out at postgraduate level and tend to be organized nationally rather than locally. Histopathology was regarded as essential for training in cytopathology by 89.5% of respondents and was mandatory according to 83.1%. Mandatory cytopathology sections of histopathology were reported by 67.3% and specific examinations in cytopathology by 55.4%. The main deficiencies in training were due to its variability; there were insufficient numbers of pathologists interested in cytology and a consequent lack of training to a high level of competence. Pathologists without specific training in cytopathology signed out cytology reports according to 54.7% of responses, more often in centres where training was 3-6 months or less duration. Although 92.2% of respondents thought that specialist cytology should not be reported by pathologists without experience in general cytopathology, that practice was reported by 30.9%, more often in centres with small workloads. The survey report recommends that 6-12 months should be dedicated to cytopathology during histopathology training, with optional additional training for those wanting to carry out independent practice in cytopathology. Formal accreditation should be mandatory for independent practice in cytopathology. When necessary, temporary placements to centres of good practice should be available for trainees intending to practise independently in cytopathology. There should be adequate numbers of pathologists trained in cytopathology to a high level of competence; some of their time could be released by training cytotechnologists and trainee pathologists to prescreen cytology slides and assess adequacy of fine-needle aspiration samples when immediate diagnosis was not required. The survey demonstrated a clear need for European and international guidelines for training in cytopathology.

Electron proportional gas counter for linear and elliptical Mössbauer polarimetry.

Design, characterization, and selected applications of a novel electron detector dedicated to conventional perpendicular- and low-angle-incidence conversion electron Mössbauer spectroscopy are presented. The setup is suitable for varying the incident angle and external magnetic fields on Mössbauer source and absorber. Test experiments were performed on alpha-(57)Fe films using a conventional single-line (57)Co(Rh) and magnetically split, (57)Co(alpha-Fe) Mössbauer sources. The integral "blackness effect" in conversion-electron Mössbauer spectra of (57)Fe isotope-enriched absorbers is demonstrated and shown to be pronounced at shallow angles of incidence. In order to determine the alignment and sign of the hyperfine field in an isotope-enriched absorber, the blackness effect is accounted for in a semiempirical way by using single-line source/absorber experimental relative intensities determined independently. This method works with high accuracy for linear polarimetry; however it is only a rough approximation in the case of nearly circular polarimetry.